Posted by LisaJ
Now this is a super cool new Science story. Have you ever wanted to make yourself invisible? Ever said "man, I wish I could just run away or hide and make everyone go away"? Maybe as a young 8 year old, trying to hide from those bullies on the playground. Or perhaps you'd like to saunter into mass inconspicuously one Sunday morning to grab one of those delicious wafers without starting a riot. Well, if this sounds like you, then your lucky day is (almost) here. Dr. Xiang Zhang and his group from the University of California have reportedly "created a material that could render people and objects invisible". They are announcing this week, in a pair of articles to be published in Nature and Science, their generation of a 3D metamaterial that exhibits a negative refractive index (thanks negentropyeater). 'Metamaterials' are apparently a manmade mixture of metal and ceramic or Teflon like materials (anyone who knows anything about this field is welcome to clarify this!) that function to bend visible light waves quite aptly. These researchers have harnessed this unusual property of the metamaterial they have created to redirect light around 3D objects to effectively disguise or 'cloak' them.
This new study represents a major progression in the field, as previously this technology could only be used to cloak very thin 2D objects. Now I'm assuming that the 3D objects they effectively made invisible in these studies were probably pretty small too, we'll have to wait until the end of the week to find out, but this is a big step closer to allowing humans to obtain their own invisibility cloaks.
This article explains that this 'new work moves scientists a step closer to hiding people and objects from visible light, which could have broad applications, including military ones. ' Which is a pretty cool application, I guess (but also a very frightening one when you think about it). I think it's pretty obvious what the greatest potential of this new technology really is: to make millions of Harry Potter fans very, very happy. You make a real invisibility cloak and you've hit a goldmine with that fanbase.
Now I am by no means a mechanical engineer, materials scientist, or an expert in this particular field. So if anyone would like to add any additional info on how this technology works it would be much appreciated. It sounds very cool, and I'd like to learn more.
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I know nothing about these materials. But if animals have evolved camouflage, and the ability to change colors, I wonder why invisibility hasn't ever evolved. Or maybe it has ...
We must fund this research to be ready for war with the Klingons!
I just hope Malfoy doesn't get his hands on some of that stuff.
And if anyone with the relevant expertise plans on commenting on this article, I have a question of my own for you: is there a minimum distance at which an object covered in such metamaterials would have to be from any other surface in order to not cast a shadow? Is there a similar limitation based on how far the metamaterials are from the light source(s)?
If it works by bending light around the wearer, wouldn't that render the wearer blind?
That's a great question Nasikabatrachus, and one that I'd love an answer to as well. From reading the story I gather that a major topic of ongoing research is to actually determine the necessary parameters to avoid shadows and glare.
this might ad a new level of complexity to the "purple dragon lives in my garage" logical fallacy
the dragon should still be detectable by other means though
I was hoping for some pictures of videos to suppliment the story. I wonder if this video is dealing with something similar?
http://www.youtube.com/watch?v=vEm4EY4IWTI
of course the first "practical" use they find for it will be to make armies invisible. Or maybe military equipment invisible to spy satellites.
Or this video?
http://www.youtube.com/watch?v=Ja_fuZyHDuk
Sounds like they're talking about materials with a negative index of refraction. Funky things, and worth googling for.
I can't see how it could fail to, if it works as described.
@ Craig: "practical" use... military...
Exactly. Although I agree with LisaJ that this development is interesting, the actual ramifications of such a device being produced in the real world are nothing short of terrifying.
Then again: I'm a pessimist, I suppose. Can any of you more scientifically astute minds contrive of some hypothetical scenarios in which the InvisiCloak(tm) might be employed for non-nefarious purposes?
S.Mortimer, thanks for the video link. That one seems spot on. This new set of studies seems to just be an extension of what they're showing in your video.
As someone who's actually worked a bit in this field, let me answer a few questions from above:
"So if anyone would like to add any additional info on how this technology works it would be much appreciated. "
As you've noted above, it works really by guiding light around a central core region. One can think of it most easily by considering it a 'refraction' process: light is 'bent' as it enters the material. The refractive index of the light varies in such a way that the light follows a path around the core and comes out on the other side as if it had never encountered an object at all. The physics isn't surprising, but until recently it wasn't thought possible to make materials with the extremely high (and low, and negative) refractive indices required to bend the light.
"is there a minimum distance at which an object covered in such metamaterials would have to be from any other surface in order to not cast a shadow? Is there a similar limitation based on how far the metamaterials are from the light source(s)?"
In principle there isn't any minimum distance, as the effect is 'perfect'. In practice, you'll probably find that there are small effects associated with objects closer than a wavelength to the cloak. Currently, the devices are so crude that they're not particularly invisible at all, i.e. they're more 'proof of principle'.
"If it works by bending light around the wearer, wouldn't that render the wearer blind?"
Yes, it would! If the light of a certain wavelength is guided away from the central core, the person (or object) inside would be receiving no light. A wearer could in principle see using other, non-visible wavelengths.
One major problem, though, is that currently such cloaks only work at a single wavelength: you'd be invisible to a certain shade of blue, for instance, but not any other. It's not clear that one can make a cloak that works over a large enough range of frequencies to completely hide from visible light.
"of course the first "practical" use they find for it will be to make armies invisible. Or maybe military equipment invisible to spy satellites."
That is what history suggests, although my impression of these kinds of technologies is that they're too delicate at this stage for use by the military. Some applications that do seem pretty likely though is communications--if these materials are better than fiber-optics, that is--and astronomy. I'm guessing that these materials could make possible a telescope that could do without lenses altogether, with the business of collecting, focussing, and magnifying light done entirely with a single membrane. That's just my silly uninformed guess, though.
Women's locker rooms... Here I come!!!
Just have to leave holes for the eyes.
Imagine there'd be some interesting artistic or decorative uses for it. If they could make it a 1-way thing, where you could see what's on the other side of a wall, but not the other way around, that would be pretty cool. Of course you may walk in to your wall a time or 2.
A suit of the stuff could probably allow a small amount of light in around the eye area without compromising the invisibility much. The invisibility probably wouldn't be very effective up close anyway, so a narrow strip of partial visibility around the head wouldn't make it any easier to spot from a distance; but the wearer's eyes would adapt to the lower light and still be able to see reasonably well.
F*cking alleged invisibility cloak breakthrough stories are in the news every year. The news media can't resist running such stories with the Harry Potter angle, even when there's only the slightest thread of substance to the story.
(The BBC website has invisibility cloak stories in Feb 2003; May, June and December 2004; and 2006)
One of these stories was in reference to an 'invisibility cloak' that was essentially just a projection screen, used in conjunction with a projector and a camera. Wear the 'cloak', stand in front of the projector, and point the camera at what's behind you. Bloody useless, that.
Wake me when something actually ships. Until then I'll assume it's someone seeking undeserved PR attention. And that any 3 dimensional materials they managed to actually 'cloak' were teeny-tiny, required lab conditions, and probably only worked on a limited range of wavelengths.
I'm not sure if it's the same story, but I read this a couple months ago. It's really only a proof of concept using microwaves, since higher frequency waves require exponentially more energy to bend. Unfortunately we're a ways away from any thing Star Trek-ish.
"If it works by bending light around the wearer, wouldn't that render the wearer blind?"
I assume it'd have some eye panels with a grid of tiny holes. From a distance, the holes would not be noticeable, but would let enough light through for seeing.
The light-bending wouldn't effect photons that don't hit the special cloak material. It's not going to act like a black hole. The light has to go into the material of the cloak in order for it to bent. It doesn't bend light that's only in the vicinity.
Invisibility cloaks? Lame... They should be working on hoverboards.
Well this is the first story I've seen myself about this particular sub-field, but it does appear that this technology has been covered by the media with grand celebrations every step of the way. Well, I guess we'll find out later this week what makes this advance so special.
If you happen to be a subscriber to the Optics InfoBase, there is an interesting article describing the mathematics involved in designing cloaking metamaterials, here: http://www.opticsinfobase.org/abstract.cfm?URI=OPN-18-6-32. Or you can buy a la carte access, with a small discount for OSA members. The same article is also in the June 2007 issue of OPN (Optics & Photonics News).
This article comes on the heels of the microwave cloaking breakthroughs discussed in the videos linked by S.Mortimer, but gives a math-heavy perspective. If I were qualified I would just describe the article, but maybe someone out there has both access and qualification. The most I can say is that the study of how light can pass around an object bears some resemblance to the study of how air passes around an airfoil.
I assume that the cloaking has been achieved with transformation based methods. You can learn more about that approach at http://en.wikiversity.org/wiki/Waves_in_composites_and_metamaterials/Transformation-based_cloaking_in_electromagnetism
Wow... weird. I was flipping through Michio Kaku's "Physics of the Impossible" in the bookstore just the other day and he had a section on invisibility devices like this. IIRC, he said doing this with visible light was likely a few years away yet. Apparently, not so much. Surprise! Now I need to go back and read what he said about the TARDIS... maybe we'll get one of those sooner than expected too. :)
Anyway, this advance would be really nifty if I didn't know that the military will use to to make killing people easier.
I know, the military aspect makes me really uneasy too. Luckily it should be along time coming before that's possible.
Speedwell: "Hey, honey, there's a story here about an invisible material."
Speedwell's dude: "Oh, cool. Do they have pictures?"
Speedwell: "....."
LisaJ
Delicious? Feh!
This will definitely give Elmer Fudd the upper hand. You better watch out you silly rabbit.
Or a few dozen Ghost in the Shell fans very, very happy. (Therm-optic camouflage, anyone?) ^__^
Stories about this kind of technology have been showing up on slashdot for some time now. From what I recall, the material acts as a waveguide for optical frequencies.
It might be possible to make someone much harder to spot with the naked eye at a distance, but making it work across IR and visible light at the same time, or making it work at very close range will be quite a hurdle.
-jcr
Whenever I read an article like this I have to check the date to make sure it's not April fool's day.
HAY GUIS HAVE YOU HERD ABOUT THA CAR THAT RUNS ON WATER?!?!
...yeah, um, i'll believe it when i see it. or in this case, don't see it. every year or so, someone puts out a story like this, and it's always lame, bullshit, or impractical. or some combination thereof.
"One major problem, though, is that currently such cloaks only work at a single wavelength: you'd be invisible to a certain shade of blue, for instance, but not any other."
That might not allow for a person to hide in plane sight, but it might be very useful for special applications.
I could see people trying to put meta-materials on their cars to avoid getting caught in speed traps.
On a more serious note, I agree with Nasikabatrachus. I think the first practical use of this technology will be as to help in some branch of physics or astronomy. Physicists have been working on negative index material for a long time. I think there is a wide range of applications for such a material.
In my mind, the real advance is the fact that they are learning to make this stuff with processes common in mass production. (Printed circuitry, packaging technology, etc)
Maybe they could be used to make the country's debt disappear?
Or George Bush? Or John McCain?
Could we drape it over red states?
Oh, can it be scanned into my laptop, and pasted into Microsoft Word? I have some reviewer comments I'm addressing right now for a paper, and it would be so much easier to just make them disappear.
Just wondering.
~Doc~
LisaJ wrote: ...Or perhaps you'd like to saunter into mass inconspicuously one Sunday morning to grab one of those delicious wafers without starting a riot....
Filch a holy cracker with no ensuing ruckus? Where would the fun be in that?
This material only works with one frequency of light and I don't believe it transmits light fully. In other words, the cloaked object would be clear red if it transmits a frequency of red light.
It is also worth noting that some researchers are working on using the same principles behind this to make REALLY cheap(IE single metal on plastic), HIGH efficiency solar cells(90% theoretical efficiency). Only problem though is that the solar cells output very high frequency AC current that is nearly impossible to rectify.
Surely, it's not just bending light around an object, it has to be done in such a way that the coherence of the image-forming light from behind the cloaked object is not disrupted in any way, otherwise you'd see something like the disturbance in the visual field that made the "Predator" partially visible in spite of its cloak.
hey, i got ya cloaking device right here right now!
"phasers optional"
Surely, it's not just bending light around an object
You say that as though it's easy with a mass less than a black hole's. :)
You're right about the phase retention, though. The "left-handed materials" have the pretty property that phase is properly accounted for, and even in the near-field (which isn't true of ordinary lenses). On the other hand, the other posters are correct when they have doubts about the bandwidth over which these materials work, and certainly there are currently problems with non-planar (i.e. cloth) configurations, etc.
The military uses of such materials would really be quite limited. They really wouldn't be useful on vehicles for a number of reasons, including the inability to cover wheels or exhaust ports, the movement of dust around, behind, and against the cloaks, the movement of the cloak as wind pushes against it, the effect of extreme temperatures on such sensitive materials, and probably many others I haven't thought off. The main use of such materials would be as a kind of super gully-suit, and as an easy way to set up difficult to locate advanced infantry positions, though they'd need to be highly durable and unaffected by rain, humidity, dust, ect.
This material only works with one frequency of light and I don't believe it transmits light fully. In other words, the cloaked object would be clear red if it transmits a frequency of red light.
I'm having a hard time wrapping my head around the difference between an opaque object that allows (say) red light to pass through versus a red tinted transparent object (like red glass). Is there a difference? If an object is opaque but does not reflect red wouldn't that make it look cyan colored?
I'm with Jon H... I'm sick to death of these teaser stories-- note that they didn't mention ANY details of the "demonstration", like did they render a car invisible or a grain of sand? Nor did they mention the very likely single wavelength limitation.
Science journalism has utterly gone to shit when stories like this do the rounds over and over again without any attempt at explaining the actual state of the art.
Only the water powered cars annoy me more....
Now you see me, now you . . . .
I'm done with this board....geeze isn't the holy cracker-wafer thing over already? do you guys have anything else besides hanging on to this? I don't know about you guys, but I'm over all this. Fine it was what it was, but come on........
Bon Voyage
Finally a science post on here that I already understand!
Metamaterials typically have a negative index of refraction(as far as I know, all regular materials have positive ones), they bend light the 'wrong way'. They have a really complicated repeated pattern structure and are probably quite expensive to make.
These invisibility cloaks work nearly perfectly, and are just as effective up close (other than the odd distortions, like in star trek!), but as someone mentioned before, they only work on extremely small ranges of wavelengths, usually in the Infrared range.
These limits mean that military application and even harry potter application are a long way off, and really, thats a good thing. Those applications are really boring. The guys who make invisibility cloaks get all the attention for being able to hide something the size of a pop can from an infrared camera, but the really interesting ones are building the various parts of computers that use light instead of electricity, like these guys. They've made a tiny box that uses these metamaterials to break light apart into its spectrum and hold onto it. thats memory storage for those who can't quite see the obvious. Photonic computers will be the next computer revolution. photons move thousands of times faster than electrons and can hold more information, instead of "on" and "off" it would be "on", "off", "red", "blue", ect...
I've also heard of these materials being used to make amazing solar cells and they have the potential to make just about anything that works with light better.
Of course, as seems to be typical of American nanotech research, the entire team of researchers can't see past idiotic applications for their work. Its always "my grandchildren will be able to make a really cool nanoweapon out of this" or "This is a long way off from being the latest scifi/fantasy craze!". Ugh. I heard a guy who had made a nano-size antenna(and radio receiver) and only thought make a boom-box out of it. It worked too, but he never thought to put it on a remote-controlled car and gradually nano-size all the other parts to make something useful. I have a tendency to shout and gesticulate wildly at the radio when these kinds of stories come on.
Still though, this is a very neat proof of the principle. Its proponents may lack vision, but this is still hard work. so, kudos to them!
I hear those tattoo-removal technicians have developed a way to remove that unsightly door-print from your posterior..... check those yellow pages!
And the Pun Of The Day award goes to nanoAl!
I asked my pooka Harvey what he thought, but my leporine pal wasn't impressed.
Uncle Martin just chuckles to himself.
One problem: The actual cloaking material is many (hundreds?) times the size of the object itself. I could see this being practical for hiding a building or something, but it really wouldn't work for individual cloaking.
I may be understanding the physics of this incorrectly, but wouldn't this only work from one direction? It couldn't be a 3d thing, could it?
I don't think the military application is very practical as long as it doesn't hide the IR wavelengths as well: all you have to do to find the invisible army sneaking up on you is put on some night vision goggles.
An invisibility cloak would be all good and well, but when is someone going to invent the Somebody Else's Problem field? Or maybe they have. It's not my problem if so.
Did we all forget that this was already in the news 2 years ago? (2006) Same exact idea from professors at Duke. Almost every article I've read online fails to give credit to the Duke professors I won't say this work is incremental, but it is surprising to see that there is no mention of the original article from 2006. At first, I thought there was a problem with my google-news pickup up old news stories.
http://www.dukenews.duke.edu/2006/10/cloakdemo.html
Man, what a bunch of BS and most of you are falling for it. Yes, they can probably do what they say they are doing, but to extrapolate that to 3d visible-light invisibility? It's laughable.
Picture what this "cloak" would have to do. All of the light falling on one side of the cloak would have to be re-emitted from the other side not just in one direction, but in all proper directions simultaneously. People have two eyes, stereoscopic vision, and there's parallax between them. This means that each eye would be seeing a different view of the background *through the cloak*!
It ain't gonna happen folks, but feel free to read Tolkien into it if you wish. This is science FICTION.
I think it's incredibly cool that pretty much every Star Trek invention comes to life. Is it a cultural influence "to explore strange new technology, to boldly go where no man has gone before", or are we simply (and so more likelier) confirming a pattern by cherry picking?
It's also incredibly illustrative to look into the differences between the shows plot devices and real life outcomes - the Alcubierre warp drive demands more energy than the mass of the observable universe holds, teleportation is pretty much non-scalable and requires receivers, cloaking devices works on specific frequencies, et cetera.
One of the posts points may remain to be adressed:
I'm not working with it, but AFAIU generally metamaterials are engineered on mesoscales to have certain properties, rather than that the properties derives from the primary materials. Think a cast of, say, spheres in a solid, instead of an alloy with different crystals.
Wikipedia has a neat definition:
One could perhaps include synthetic 'atoms' here, i.e. nanoscale atomic clusters that starts to attain unique chemical properties different from its constituents as the number of atoms increases from a few, but before the cluster is large enough to attain bulk properties.
@ t-1000:
How is that supposed to work? Usually "solar cells" are diodes, so they come with their own rectification. The described structure could be a Schottky diode, assuming that the plastic is a semiconductor.
But on the surface of it, this is all too mystifying. References please!
I have an invisible friend. He loves you and wants to save you from your sin. Refer to John chapter 3 in the Bible.
I have an invisible friend. He loves you and wants to save you from your sin. Refer to John chapter 3 in the Bible.
Maybe Ninjas will beat the Harry Potter fans to geek nirvana.
A nano material has been developed which absorbs 99.9% of light.
http://www.abc.net.au/science/articles/2008/01/16/2139711.htm
To Ross Nixon (#59):
Let us pray, my brother, to know how he does that.
But, seriously, there is a difference between "invisible for the eyes" and "invisible for radars". For radars, this is different because the radar sends a signal and "sees" the target by the fact that this signal is returned. The solution is therefore to find a material which totally absorbs the electromagnetic waves instead of reflecting them.
For "invisibility for eyes", this is much more complicated since we want to see what is behind the object and in all directions.
Yes... one step closer to fulfilling my life long dream to become Solid Snake...
Having worked with stealth technology in a prior life, I am pretty confident that this will find numerous military applications. I'd be surprised if DARPA wasn't heavily involved in this project already.
IIRC, an F-117 was shot down by with small arms fire. Well, it's hard to see on radar* (and stealth is set up for numerous frequencies), not so hard to see with the Mark 1 Mod 0 Eyeball. If it can work with sky blue freqs, that goes a long way to invisify aircraft. That extends to all those unmanned aerial vehicles, too - both the surveillance and death dealing types.
If, as it seems to, it works in near IR, there is an application the military wants big time - reducing heat signatures. I don't expect every application would involve "see only what's behind me" but would also include "my hot spot is somewhere else", i.e. prevent IR fom going in certain directions.
I'm rather doubtful about the ability to make a cloth do these things, but hey, truth is stranger than friction.
*Don't fall for that "radar signature of a bird" BS - that means nothing and is presented for general officers to shut them up (answer their stupid questions). A real signature is defined in multiple threat frequencies, each of which gets a radial plot identifying spikes of energy return. Bi-static or multi-static radar systems can track stealthy planes just fine; I'm talking mono-static radar (i.e. single co-located transmitter & receiver)
Daniel R, stealth uses various techniques to reduce radar return. If you look at the early flat-plate designs, they are clearly set up to reflect energy away from its origin.
Newer designs use more radar absorbing materials, but also reflect signals away, but in a more scattering manner (same energy over a larger expanding beam).
They also deal with multiple frequencies. They used to say from "DC to daylight" for spectrum. Part of the problem has been that materials that are optimised to absorb a certain freq also reflect other freqs back, with greater return energy. It's been a balancing act, like any other engineering challenge. Not that you heard this from me...
As usual, let's be careful.
Is it :
"Scientists say they are a step closer to developing materials that could render people and objects invisible. "
or
"The press interprets that scientists say they are a step closer to developing materials that could render people and objects invisible."
You can check the MURI page on Metamaterials at Prof. X.Zhang's lab to get a good introducton;
http://xlab.me.berkeley.edu/MURI/MURI.html
You won't find a word on "materials that render people invisible".
True Bob (#64): thanks for the info, I didn't know...
I set up a web page some years ago that lists 20 "must have" inventions. I update it every year and attempt to keep track of the latest developments in a range of fields from nuclear fusion to practical time travel. I rate each one on a scale of 0-10 every year to see what overall progress has been made, and I also provide links to any interesting web pages I find.
I'd be grateful if anyone interested would take a look, and even more grateful to anyone who bookmarks my page and notifies me of any developments like invisiblity so I can update the page when necessary.
Where is it? Oh - glad you asked. http://www.herring.pwp.blueyonder.co.uk/inventions.htm
http://www.livescience.com/animals/041116_butterfly_light.html
Do we have all butterfly species cataloged yet? :)
So the receptionist says to the psychitrist your next patient thinks he is inviable, the doctor says,
"tell him I can't see him now."
Scaling is a problem, nanomaterials are notoriously difficult to recreate in large quantities for cheap. Part of me strongly wants people to fail at this, just because of the implications for privacy, which has already been beaten to the ground and clubbed enough. Imagine now if every public police surveillance camera, in places like Britain and increasingly the US, was cloaked so you wouldn't even know you're being watched.
However as a poster above noted, this may not be that practical for military use. Especially considering that they have yet to achieve a truly amazing feat of dark matter analogues: Now if they had a material that was impervious to all EM radiation, then it might have real military applications because you could cloak anything from radar, though I assume communications might be problematic.
That should have been your nexst patient thinks he is invisable, the doc says, "tell him I can't see him now."
#28 "Do they have pictures?"
If the object actually is invisible i think you'd be sadly dissapointed by any pictures they took of it.
El Herring (#67), that's awesome. Thanks for the link.
Again, let's not all jump on the bandwaggon of chating about invisible people and objects.
Prof.Zhang's lab own web page says (see my post #65 for the link) it clearly :
Research Goals :
Not exactly "rendering people and objects invisible". That's what our usually pathetic and ignorant press is making out of it, of course, they like sensational titles more. It sells more commercials.
I think any 'cloak' would need a fixed shape, eg sphere, cylinder, but could not just be a piece of material you could drape over anything. Light entering at a certain point and angle A, has to leave at a point B at the same angle, and at the same phase as it would have done had it passed straight through. Drape the cloak over a different object, and the exit point wouldn't be at B anymore. The new exit point, C, would be at a different distance from the entry point so the phase would need changing too.
LisaJ,
This is FALSE !
The two articles to be published are :
[1] Jason Valentine, Shuang Zhang, Thomas Zentgraf, Erick Ulin-Avila, Dentcho A Genov, Guy Bartal and Xiang Zhang, "Three Dimensional Optical Metamaterial Exhibiting Negative Refractive Index", Nature, in press.
[2] Jie Yao, Zhaowei Liu, Yongmin Liu, Yuan Wang, Cheng Sun, Guy Bartal, Angelica Stacy and Xiang Zhang, "Optical Negative Refraction in Bulk Metamaterials", Science, in press.
There is a VERY BIG difference between "a material that exhibits a Negative Refractve Index", and "a material that can render a three dimensonal object invisible".
You are not going to get an invisibility cloak here.
This American Life had the perfect description of invisibility. In their show where they asked people whether they'd prefer the power to fly or the power to become invisible, one of the respondents said "invisibility is for fearful, crouching, masturbators."
negentropyeater wrote: "Not exactly "rendering people and objects invisible". That's what our usually pathetic and ignorant press is making out of it, of course, they like sensational titles more."
To be fair, I bet it's actually coming from Zhang's university's media relations office, and the news orgs are just parroting the press release.
It could work by bending the relected light from any object. When light hits an object, it reflects far less light than it recieves, simply bending the reflection of whatever light is not absorbed would do the trick. It would make seeing the object rather difficult, but I think in strong light, you'd see something. You might not know what you're seeing though
I think it would be interesting to see. I don't think an object will be literally invisable, but what you do see would be so strange that you wouldn't recognize it as an object, or perhaps as the object that it is.
I dont think it would work in strong direct light though, the contrast would be to easy to spot.
As for light passing around the object, that has some problems in physics as well, seeing that light would still be [randomly] reflected according to the contours of the object. I would think it might take a bit of apparatus to make it work, which then becomes problematic for whatever you wish to 'cloak', because you'd have to cloak the cloak so to speak and so on.
In low light, it would be rather awsome though.
negentropyeater, I also noted that the object they've apparently successfully 'cloaked' is likely to be be very small, and that this really isn't the case of a perfect invisibility cloak. So I am not expecting to see that they've made a human invisible, or even a significantly sized 3D object. Thank you for pointing this out to me though, I will change up the wording there to make a more accurate statement.
There's a difference between saying that these materials may, one day, lead to invisibility cloaks (which is probably what Zhang repeated, as he said a while back already) and what comes out in the press.
It's always the problem with communication on this kind of scientific breakthrough. Scientists tend to be cautious and add some prospective statements about what may happen in the future (or may not), but the press elminates the cautiousness and focusses on the prospective.
http://www.me.berkeley.edu/announcements/zhang_times07.html
There is one fairly obvious and probably not-too-difficult application for this technology: if you can make a device that refracts three wavelengths of roughly RGB, you could have a very, very thin screen. So I would bet most likely the first real-world application for this technology will be to develop almost 2D televisions.
Metamaterials greatest strength, right now, is that they allow a lot of microwave devices to be created which are smaller than the traditional devices or allow steering of electromagnetic waves. Unfortunately, the drawback is that, because some of these objects work only at resonance, their frequency range is limited (i.e. the post above mentioning that they only work at one wavelength...not strictly true, but the bandwidth is very limited) and they can be quite lossy (i.e. you'll need a large signal strength or good amplification to compensate for the losses). Another problem with the materials is that they are very sensitive to any sort of error in manufacturing. Therefore, as the wavelength becomes smaller, any unintended defect is production becomes more pronounced. Therefore, it becomes harder to create the desired behavior in, say, the visible light frequencies because of the very small wavelength. This is true, at least, when dealing with materials that are designed to include resonators or using a material called a composite left-right hand transmission line. I guess the photonics people use photonic band-gap crystals, and I'm not sure what the challenges are with working on those. I would assume, however, that they work along the same lines as a lot of the same concepts are involved in their use.
I think in the long run, they may come up with a lot of cool optical devices using metamaterials. When some of the first research was done on metamaterials by Veselago, he was talking about the ramifications of such a material when no one knew how to create it. It sat for decades before anyone was able to come up with something that even worked. In the decade since the first metamaterial was developed, there has been an awful lot of progress.
And yes, the military is very interested in metamaterials...not simply as cloaking devices, which is probably a ways off, but for all the other things MTMs can be used for.
Probably someone said something by now but metals, ceramics and Teflon are as different as you can get in the materials world. Teflon is a polymer, and thus neither a metal nor a ceramic. Ceramics are generally the compound of a metal with a non metal (like rust, iron and oxygen, or salt, sodium and chloride).
The intriguing material there is teflon. Ceramics can have very strange properties (glass is a ceramic, for instance) and metals can conduct electricity, but teflon is more known for it's extreme chemical inertness and it's extremely low coefficient of friction (explaining its use in frying pans). From what I understand, invisibility metamaterials depend on generating very special patterns of electromagnetic fields, so the use of a non-conducting polymer is kind of strange, but I'd have to read the article to say for sure.
I can think of a non-military use.
We could wrap them around forests to stop the trees from falling.
negentropyeater wrote: "It's always the problem with communication on this kind of scientific breakthrough. Scientists tend to be cautious and add some prospective statements about what may happen in the future (or may not), but the press elminates the cautiousness and focusses on the prospective."
You're missing the point. It's not a direct transmission from the scientist to the press.
Between the press and the scientist there are people at the university who are trying to drum up publicity for the university. It's their job to pump up these things and feed them to the press. The scientist can be as circumspect as he wants to be, but the PR flacks at the university will promote the most wild-eyed speculative version of the story that they can dream up.
Yes, the press does a horrible job, but the university media relations departments are a big part of the problem. They're why so many media outlets promote an identical ludicrous interpretation of the facts.
The great news for guys?
I could make you invisible.
The bad news?
It quits if you get an erection.
http://boskolives.wordpress.com/
This should eliminate all the media induced hyperbole, here's the paper in Nature:
http://www.nature.com/nature/journal/vaop/ncurrent/full/nature07247.html
@ Torbjörn Larsson, the research I am talking about uses nanoantennas. Just like regular radio antennas, except these antennas work at the frequency of infrared light. They are about 80% efficient, but unfortunately they have a short frequency range.
Ref: http://www.physorg.com/news137648388.html
I just hope Catholic priests don't start wearing robes made of this stuff, or the altar boys won't have a chance.
Hmm... only small objects can be cloaked? Perfect for hiding your beer from your mooching brother-in-law!
"Hokey religions and ancient weapons are no match for a good wand at your side, kid."
I can't believe this rubbish has got repeated here! I've come to expect it from the usual MSM offenders who refuse to cover any LHC story unless its along the lines of "OMG!BIG BANG! 27km TUNNEL! WTF!" But to see it regurgicated here at Pharyngula? Yuck.
Forget this 007 drivel PZ, negative refractive index materials have some fascinating potential applications. One which should interest any biologist is the use of lenses in the direct imaging of molecules. These materials could mean that optical frequency light could be focussed on objects much smaller than its wavelenth would normally allow in a normal lens.
Just realized that this was a guest blog post. Shame on you LisaJ for falling for this sensationalized garbage.
You mean nano-objects, not a beer can.
In order to bend light completely and perfectly around an object of the dimensions of even a beer can, so as to make it dissapear, it's far from determined if this technology can even be scaled up and perfected (NRI and Figure of Merit) in order to do this. So in reality, they have no idea if this is a step towards invisibility cloaks, but for sure, it's very interesting for a range of other applications.
But of course all the titles in the press are about "invisibility cloaks" and not about all the potential real applications.
Joey, I apologize. I have only been coming to this blog for about 6 months and hadn't heard of this story before, so I did not know the history of it. However, I do realize that this is a very small step and does not really mark the creation of a true invisibility cloak, or anything of much significance yet. I did think it was a neat topic though, worthy of discussion, and something outside of what I think of in my lab everyday.
Not if it's a matrix for a structure of metal or semiconductor material. Say conducting threads cast in plastic, to make grids et cetera.
@ t-1000
Ah, I see, so "solar cells" by application. Thanks!
Yes, they would be resonating for efficient collection. Hmm, I still believe my proposal (or at least a thin, so also flexible, layer of semiconducting amorphous silicon in between) would fix rectification at the same scale as the antenna patterning.
I thought they'd be better off following the optic fibre route? since the principal had already been shown to work to some degree a few years back ( google invisible jacket )
A fine mesh material of optic fibres, so looking at one side, you are seeing what is on the other side? rendering the item underneath the material near optically 'invisible'.
add in a mylar type film undrneath to reduce thermal footprint if you wish, or on a more permanent use, apply those ceramic thermal reduction materials under the the lot.
p.s. I'm with Dan on the Klingons. :D